When Do You Actually Need to Worry About Household Mold?

Mold has been in the news a lot recently for a really sad reason: On September 22, three transplant patients at the University of Pittsburgh Medical Center died from a fungal infection. Officials believe the mold that killed the patients was a common type that's often found lurking in households. Yikes.

But before you go bleaching your entire home from top to bottom, there are a few things you need to know about household mold. Most important: This case is extremely rare.

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The type of mold that caused the Pittsburgh infections is only a threat to people with weak immune systems, says Richard Shaughnessy, IV, DO, program director at the University of Tulsa Indoor Air Program and internationally recognized indoor air quality expert.

"People who are recovering from transplant operations have a very compromised immune system at that point in time, so any exposure can be magnified," he explains. "But that is not representative of the general population. The typically healthy adult is not going to react adversely to low-levels of molds within the environment."

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In fact, mold can actually be a good thing. "Mold is common — it's everywhere. We don't find ourselves in a sterile environment, nor would we want to," Dr. Shaughnessy says. "Many molds are beneficial in terms of penicillin and other medicines, so it's not something that we want to run from and be alarmed to the extent that we're going to panic."

But the question remains—how are we supposed to know the difference between good and bad types of mold?

Unfortunately there is no one-size-fits-all answer. Everyone has a different level of susceptibility, which means that different mold species can have widely different effects on different people.

"The truth is, you can put some people into a mold factory and they're not going to react," Shaughnessy says. "We don't know at what level the 'typical' person is going to react adversely."

However, there are a few absolutes in the world of mold. First off, mold thrives in dampness, and when you smell something funky, it's time to get busy.

"When you have that dank, dark, mildew-y-type smell — that is unhealthy," Shaughnessy says. "Many respiratory problems have been associated with children and adults who have constantly been exposed to a damp, wet environment."

Also, size matters: "If you have a few square feet of mold growth, the EPA is going to tell you that you can put on gloves to clean it and remove it," he says. "Once you get upwards to 20 or 30 square feet, you should begin to take it more seriously in terms of trying to contain it. And upward of 100 square feet — let's say a section of 10 feet by 10 feet — that's where you need to call the professionals."

What to Do if You Find Mold in Your Home

If you need to remove mold from your home, Shaughnessy strongly suggests first finding and fixing the source of the problem. "Identify the source of contamination. Is it condensation, a leak, a plumbing break?"

If the problem stemmed from mother nature, such as a flood, he says the "huge amounts of bacteria that come in with floodwater and sewage contamination could bring in other allergens and dust mites," so mold may not always be the only bad guy.

And if you decide to call in the professionals, Shaughnessy suggests checking out the mold investigator's experience and references first.

"Pay much more attention to those factors instead of a piece of paper that says they're certified," he says. After all, he took part in a 2013 ABC news report that uncovered a number of scam investigators who preyed on people's fears, charging them thousands of dollars for unnecessary mold removal. "They may be certifiable, but they may not be the one who should help you with the problem."